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* [PATCH 23.11 1/3] net/gve: send whole packet when mbuf is large
@ 2025-12-23 22:30 Joshua Washington
  2025-12-23 22:30 ` [PATCH 23.11 2/3] net/gve: clean when insufficient Tx descriptors Joshua Washington
  2025-12-23 22:30 ` [PATCH 23.11 3/3] net/gve: add DQO Tx descriptor limit Joshua Washington
  0 siblings, 2 replies; 3+ messages in thread
From: Joshua Washington @ 2025-12-23 22:30 UTC (permalink / raw)
  To: stable, Thomas Monjalon, Junfeng Guo, Jeroen de Borst,
	Rushil Gupta, Joshua Washington
  Cc: Ankit Garg

Before this patch, only one descriptor would be written per mbuf in a
packet. In cases like TSO, it is possible for a single mbuf to have more
bytes than GVE_MAX_TX_BUF_SIZE_DQO. As such, instead of simply
truncating the data down to this size, the driver should actually write
descriptors for the rest of the buffers in the mbuf segment.

To that effect, the number of descriptors needed to send a packet must
be corrected to account for the potential additional descriptors.

Fixes: 4022f9999f56 ("net/gve: support basic Tx data path for DQO")
Cc: stable@dpdk.org

Signed-off-by: Joshua Washington <joshwash@google.com>
Reviewed-by: Ankit Garg <nktgrg@google.com>
---
 .mailmap                     |  1 +
 drivers/net/gve/gve_tx_dqo.c | 53 ++++++++++++++++++++++++++----------
 2 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/.mailmap b/.mailmap
index 96b7809f89..eb6a3afa44 100644
--- a/.mailmap
+++ b/.mailmap
@@ -119,6 +119,7 @@ Andy Green <andy@warmcat.com>
 Andy Moreton <andy.moreton@amd.com> <amoreton@xilinx.com> <amoreton@solarflare.com>
 Andy Pei <andy.pei@intel.com>
 Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
+Ankit Garg <nktgrg@google.com>
 Ankur Dwivedi <adwivedi@marvell.com> <ankur.dwivedi@caviumnetworks.com> <ankur.dwivedi@cavium.com>
 Anna Lukin <annal@silicom.co.il>
 Anoob Joseph <anoobj@marvell.com> <anoob.joseph@caviumnetworks.com>
diff --git a/drivers/net/gve/gve_tx_dqo.c b/drivers/net/gve/gve_tx_dqo.c
index 95a02bab17..a4ba8c3536 100644
--- a/drivers/net/gve/gve_tx_dqo.c
+++ b/drivers/net/gve/gve_tx_dqo.c
@@ -74,6 +74,19 @@ gve_tx_clean_dqo(struct gve_tx_queue *txq)
 	txq->complq_tail = next;
 }
 
+static uint16_t
+gve_tx_pkt_nb_data_descs(struct rte_mbuf *tx_pkt)
+{
+	int nb_descs = 0;
+
+	while (tx_pkt) {
+		nb_descs += (GVE_TX_MAX_BUF_SIZE_DQO - 1 + tx_pkt->data_len) /
+			GVE_TX_MAX_BUF_SIZE_DQO;
+		tx_pkt = tx_pkt->next;
+	}
+	return nb_descs;
+}
+
 uint16_t
 gve_tx_burst_dqo(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 {
@@ -88,7 +101,7 @@ gve_tx_burst_dqo(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 	const char *reason;
 	uint16_t nb_tx = 0;
 	uint64_t ol_flags;
-	uint16_t nb_used;
+	uint16_t nb_descs;
 	uint16_t tx_id;
 	uint16_t sw_id;
 	uint64_t bytes;
@@ -122,11 +135,14 @@ gve_tx_burst_dqo(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 		}
 
 		ol_flags = tx_pkt->ol_flags;
-		nb_used = tx_pkt->nb_segs;
 		first_sw_id = sw_id;
 
 		csum = !!(ol_flags & GVE_TX_CKSUM_OFFLOAD_MASK_DQO);
 
+		nb_descs = gve_tx_pkt_nb_data_descs(tx_pkt);
+		if (txq->nb_free < nb_descs)
+			break;
+
 		do {
 			if (sw_ring[sw_id] != NULL)
 				PMD_DRV_LOG(DEBUG, "Overwriting an entry in sw_ring");
@@ -135,22 +151,29 @@ gve_tx_burst_dqo(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 			if (!tx_pkt->data_len)
 				goto finish_mbuf;
 
-			txd = &txr[tx_id];
 			sw_ring[sw_id] = tx_pkt;
 
-			/* fill Tx descriptor */
-			txd->pkt.buf_addr = rte_cpu_to_le_64(rte_mbuf_data_iova(tx_pkt));
-			txd->pkt.dtype = GVE_TX_PKT_DESC_DTYPE_DQO;
-			txd->pkt.compl_tag = rte_cpu_to_le_16(first_sw_id);
-			txd->pkt.buf_size = RTE_MIN(tx_pkt->data_len, GVE_TX_MAX_BUF_SIZE_DQO);
-			txd->pkt.end_of_packet = 0;
-			txd->pkt.checksum_offload_enable = csum;
+			/* fill Tx descriptors */
+			int mbuf_offset = 0;
+			while (mbuf_offset < tx_pkt->data_len) {
+				uint64_t buf_addr = rte_mbuf_data_iova(tx_pkt) +
+					mbuf_offset;
+
+				txd = &txr[tx_id];
+				txd->pkt.buf_addr = rte_cpu_to_le_64(buf_addr);
+				txd->pkt.compl_tag = rte_cpu_to_le_16(first_sw_id);
+				txd->pkt.dtype = GVE_TX_PKT_DESC_DTYPE_DQO;
+				txd->pkt.buf_size = RTE_MIN(tx_pkt->data_len - mbuf_offset,
+							    GVE_TX_MAX_BUF_SIZE_DQO);
+				txd->pkt.end_of_packet = 0;
+				txd->pkt.checksum_offload_enable = csum;
+
+				mbuf_offset += txd->pkt.buf_size;
+				tx_id = (tx_id + 1) & mask;
+			}
 
-			/* size of desc_ring and sw_ring could be different */
-			tx_id = (tx_id + 1) & mask;
 finish_mbuf:
 			sw_id = (sw_id + 1) & sw_mask;
-
 			bytes += tx_pkt->data_len;
 			tx_pkt = tx_pkt->next;
 		} while (tx_pkt);
@@ -159,8 +182,8 @@ gve_tx_burst_dqo(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 		txd = &txr[(tx_id - 1) & mask];
 		txd->pkt.end_of_packet = 1;
 
-		txq->nb_free -= nb_used;
-		txq->nb_used += nb_used;
+		txq->nb_free -= nb_descs;
+		txq->nb_used += nb_descs;
 	}
 
 	/* update the tail pointer if any packets were processed */
-- 
2.52.0.351.gbe84eed79e-goog


^ permalink raw reply	[flat|nested] 3+ messages in thread
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2025-12-23 22:30 [PATCH 23.11 1/3] net/gve: send whole packet when mbuf is large Joshua Washington
2025-12-23 22:30 ` [PATCH 23.11 2/3] net/gve: clean when insufficient Tx descriptors Joshua Washington
2025-12-23 22:30 ` [PATCH 23.11 3/3] net/gve: add DQO Tx descriptor limit Joshua Washington

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